Just as a rolling stone gathers no moss, it isn’t easy to quit when no one can replace you.

That’s why local indie music mainstay Mario Escovedo will be on stage tonight at the Casbah, heading up the 16th annual “Exile on Kettner Boulevard” Christmas Eve concert bash. Never mind that he will be doing so a full six years after he announced that he and his band would be handing the torch over to, well, that was the problem.

“It was an idea that kind of ran off on its own and kept getting bigger,” said singer-guitarist Escovedo of the annual, free-admission tribute to the music of the Rolling Stones.

“The first ‘Exile’ show was in 1993 and we hadn’t really thought about it continuing so long. Plus, musicians who play in different bands are definitely busy around the holiday season. But (Casbah co-owner) Tim Mays couldn’t find a band to take over after we said 2003 would be our last year. When he asked us to come back in November of 2004, because the Casbah would otherwise have to go dark that night, it was hard to walk away.”

Ironically, Escovedo and his now-former band, The Dragons, were not supposed to have played at the first “Exile” gig. Local music mainstays Uncle Joe’s Big Ol’ Driver was slated to perform the show, which had been devised as a festive vehicle for area musicians and fans to celebrate the holiday season together to a live, all-Stones soundtrack.

But time waits for no one, including Uncle Joe’s, which had to cancel at the second to last moment.

The Dragons stepped in to save the night, after having hastily assembled a repertoire of songs by the Stones that focused on the English band’s classic 1972 double-album, “Exile on Main Street.” Since then, it’s been nothing but happy Christmas Eve shows, as Escovedo and various musical pals play salt of the earth songs designed to make listeners sway with satisfaction.

“Playing a Stones’ song like ‘Loving Cup’ or ‘Shine a Light’ is magical,” Escovedo, 46, said. “And it makes you appreciate the Stones more, especially when you’re playing their songs with such talented musicians. ‘Exile’ is an album you can revisit and find something new every time you hear it.”

For the first year or two, there were nearly as many musicians on the stage as people in the audience, recalled Escovedo, who by day works on the assignment desk at KFMB-TV Channel 8. But the crowds grew each year, as did the quality of the music and the caliber of guest stars.

Now, the event has grown to the point that a second group, Exile Band II, co-led by Escovedo and Shambles’ co-leader Bart Mendoza, tonight will play a mid-show set of “Under My Thumb,” “This Could Be the Last Time” and other 1960s Stones favorites.